Project Abstract An estimated 86 million adults in the United States have prediabetes, and low-income Latino and African American adults have disproportionately high rates compared to non-Hispanic adults. Structured lifestyle interventions can prevent or delay type 2 diabetes in these at-risk populations and now are widely offered at community organizations and health systems. Yet, uptake of and engagement in available formal programs is very low. Low-income racial and ethnic minority adults in particular face multiple barriers to navigating, engaging in, and sustaining involvement in available programs and lifestyle behaviors found to decrease progression to diabetes. It is critically important to develop and evaluate innovative approaches to increase uptake, engagement, and maintenance of gains in diabetes prevention activities. Peer support has been shown in ours and others' effectiveness trials to be a sustainable, effective approach for positive behavior change and improved outcomes in adults with diabetes and other chronic conditions. Our pilot work suggests such approaches are feasible and acceptable among low-income Latino and African American patients with prediabetes to prevent chronic disease and better navigate their health care systems to obtain healthy lifestyle counseling and support. However, such peer support models among Latino, African American, and other low- income adults with prediabetes have not yet been rigorously evaluated. Accordingly, we propose a parallel, two-arm randomized controlled trial in primary care centers in two different health systems that serve multi- ethnic communities with a high concentration of Latinos and African Americans and diverse socio-economic backgrounds. We will compare enhanced usual care (providing referrals to diabetes prevention programs and resources) with a model of a structured behavioral change intervention supplementing enhanced referral to programs and resources with peer support to help link adults with prediabetes to existing health system and community diabetes prevention programs, to support their engagement in formal programs, maintain achieved gains, and support participants to initiate and sustain healthy behaviors to prevent diabetes.